Liquid Reservoir Research Articles

FE sloshing modelling in bidimensional cavity using wave equation

Tuned liquid column damper (TLCD) is a kind of passive damper that use water sloshing motion to control structural vibration in tall buildings, wind turbines and ships. This paper presents finite element analysis of sloshing in 2D water tank using a pressure based Eulerian approach. The fluid domain is discretised by an isoparametric quadrilateral finite element. The cavity was modelled with rigid contours and free surface in order to study the decoupled liquid reservoir. Next, the cavity was coupled to a flexible structure with free vibration and forced vibration. The numerical results obtained by the created program were validated using experimental results [1] presenting acceptable errors with less than 5k elements.

Dynamical behavior of liquid in reservoir of revolution under harmonic force disturbance in the below resonant frequency range

Dynamical behavior of liquid in reservoir of revolution under harmonic force disturbance in the below resonant frequency range

Probabilistic approach of resource assessment in Kerinci geothermal field using numerical simulation coupling with monte carlo simulation

The Kerinci geothermal field is one phase liquid reservoir system in the Kerinci District, western part of Jambi Province. In this field, there are geothermal prospects that identified by the heat source up flow inside a National Park area. Kerinci field was planned to develop 1×55 MWe by Pertamina Geothermal Energy. To define reservoir characterization, the numerical simulation of Kerinci field is developed by using TOUGH2 software with information from conceptual model. The pressure and temperature profile well data of KRC-B1 are validated with simulation data to reach natural state condition. The result of the validation is suitable matching. Based on natural state simulation, the resource assessment of Kerinci geothermal field is estimated by using Monte Carlo simulation with the result P10-P50-P90 are 49.4 MW, 64.3 MW and 82.4 MW respectively. This paper is the first study of resource assessment that has been estimated successfully in Kerinci Geothermal Field using numerical simulation coupling with Monte carlo simulation.

Simulation-driven design of a passive liquid cooling system for a thermoelectric generator

Active cooling of thermoelectric generators (TEGs) is problematic since mechanical devices such as pumps and fans draw a high proportion of the limited power generated. Increasing the coolant fluid flow rate is typically a scenario of diminishing gains since the increased TEG power can be more than offset by the increase in power required for the fluid mover. Passive air cooling is an option, however the high air-side thermal resistance results in poor TEG power performance and low thermal efficiency. To address these issues, and others, a passive single phase liquid thermosyphon cooling system for use with TEGs has been designed, computationally simulated and experimentally tested. The novelty of the cooling system centres not only on the hot-side heat exchanger design, but also on the use of an open liquid reservoir as a dual-purposed heat store and air-side heat sink. This results in an effective source-to-sink heat exchange system that is entirely passive while providing effective cooling. This work describes the Simulation-Driven Design approach used to design the system for an example of a single TEG, experimental verification of the simulation results and TEG performance characteristics with the new cooling system.

Improving oil recovery in the Wolfcamp unconventional liquid reservoir using surfactants in completion fluids

Well performance after stimulation in unconventional liquid reservoirs (ULR) can be enhanced by altering rock wettability, and by moderately reducing interfacial tension (IFT) using surfactants in completion fluids. However, ULR lithology plays a major role in surfactant selection due to rock-fluid interactions having direct impact on oil recovery. This experimental study evaluates and compares the efficiency of different groups and blends of surfactants on recovering liquid hydrocarbons from siliceous and carbonate Wolfcamp shale cores by analyzing the effects of lithology, oil and surfactant type on wettability and IFT alteration, and their impact on imbibition and oil recovery.ULR wettability was determined by contact angle (CA) experiments, and its alteration was evidenced when adding surfactants to completion fluids. The results showed that at field-used concentrations, all tested surfactants altered wettability from oil and intermediate-wet to water-wet. These findings were consistent with zeta potential results when assessing surfactant solution film stability on siliceous and carbonate shale rock surfaces as an indication of water wetness. In addition, IFT between crude oil and completion fluids was measured to gauge IFT reduction by surfactants, showing higher reductions by anionic surfactants compared to nonionic and blended surfactants. Finally, imbibition potential for completion fluids with and without surfactants was tested in spontaneous imbibition experiments. Oil recovery from Wolfcamp shale cores was tracked in real time, and CT scan technology was simultaneously used to monitor frac fluid penetration in ULR cores. The results showed that cores submerged in completion fluids with surfactant additives have higher hydrocarbon recovery and better fluid imbibition than those in frac fluids without surfactants. In addition, siliceous shale cores had higher oil recovery and fluid penetration when anionic surfactants were used. Conversely, carbonate shale cores showed better hydrocarbon recovery and penetration when submerged in nonionic-cationic surfactants. Hence, it can be concluded that the addition of surfactants to completion fluids improved oil recovery by wettability alteration and IFT reduction, and core lithology, oil and surfactant type impacted fluid imbibition and oil recovery and should play a major role on surfactant selection. These findings give important understanding for designing completion fluid treatments and flowback schedules for these ULR.

Prediction of steady-state freeze front position during 3D printing of microstructures

Additive manufacturing with alloys at micro and meso-scales is an emerging technology with applications in printed, flexible or conformable electronics, solar energy and biomedical science. Among various additive manufacturing techniques, the recently introduced 3D-freeze-printing technique has the potential to revolutionize printed circuits, sensors and conformal wearable electronics. In 3D-freeze-printing, low melting point alloys are dispensed through a micro-scale nozzle on a cooled substrate and frozen simultaneously to create three-dimensional structures. The quality of the 3D printed structures relies on a continuous liquid-to-solid phase change of the printed filamentary structures through the propagation of a freeze-front. Thus to achieve stable printing of complex 3D structures, the study of freeze-front position is critical. In this paper, we present a thermal model to predict the steady-state freeze-front position during the freeze-printing process. Thermal modeling can aid in predicting parameter dependent process response and help achieve robust 3D printing with high accuracy and high throughput. Owing to the disparate length scale and nature of materials, quasi 1D energy equations are developed to model the printed structures and dispensing nozzle, while 2D energy equations are used to model the heat transfer from the liquid alloy reservoir. A finite volume method with a modified variable time-step approach is used for the discretization of governing differential equations to find the freeze front. The validity of this model was experimentally tested for three cases: vertical printed structures with and without a connected nozzle and a horizontally printed structure with a connected nozzle. It was shown that the model predicted the freeze-front position with high accuracy for various substrate temperatures and process conditions.

Experimental characterization of droplet dispensing in electrowetting-based microfluidics

In this study, the effect of various parameters on the dispensed droplet size in microchannels based on the electrowetting on dielectric technique is experimentally investigated. A printed circuit board (PCB)-based microfluidic chip is used as a platform for the experiments. A crescent configuration for the channel electrodes is fabricated, which leads to a higher electrowetting force which improves the motion of the droplet. In addition, two electrode designs are proposed, which provide a nearly constant overlapping length on the reservoir electrode. The focus of this paper is on the geometry of the reservoir and the channel electrode; therefore, the channel dimensions, surface conditions, and applied voltage are kept constant. The experiments are performed for various reservoir liquid volumes and different electrode shapes of the reservoir and the microchannel. The results show that decreasing the length of the small reservoir electrode reduces the size of the dispensed droplet. It is also observed that using a channel electrode curved in the opposite direction of the droplet motion leads to a smaller dispensed droplet.

Microfabricated emitter array for an ionic liquid electrospray thruster

We have fabricated needle-shaped emitters on a Si wafer by a MEMS process, and measured the voltage–current characteristics and the frequency dependence of a bipolar pulse voltage for ionic liquid electrospray thrusters, which can be mounted on nanosatellites (10 kg). Although the extracted current did not increase with increasing number of emitters, probably owing to the lack of uniformity of the emitters fabricated, we have demonstrated that the emitted current depends on the gap distance between the emitter and the extractor grid electrode, and low frequencies of the bipolar pulse voltage are desirable for thruster operation. Moreover, the Bosch process is required for fabricating a reservoir of ionic liquid, which prevents undesirable electrical short circuits, and the minimum emitter pitch to prevent loss of ion beams to the extractor is estimated to be about 400 µm.

Potential of Improving Oil Recovery with Surfactant Additives to Completion Fluids for the Bakken

Fracture treatment performance in Bakken liquid-rich shale reservoirs can be improved by altering rock wettability from oil-wet to water-wet. The use of surfactant additives for altering wettability also results in alteration of the interfacial tension (IFT). The Young–Laplace equation relates the capillary pressure to IFT and contact angle. Thus, it follows that capillarity is significant in nanopores associated with unconventional liquid reservoirs (ULRs) and complex as the contact angle (CA) and IFT varies simultaneously. This study carefully evaluates these interactive variables and compares the performance of anionic, nonionic, blended, and complex nanofluid (CnF) surfactants in recovering liquid hydrocarbon from siliceous and carbonate Bakken shale cores through spontaneous imbibition experiments. In addition, we also analyze the effect of wettability, surfactant adsorption, and IFT alteration on the process. CA measurement is used in determining the original wettability of Bakken cores, as well as ...

Pool boiling enhancement through contact line augmentation

In addition to transient conduction, microconvection, and microlayer evaporation, contact line region heat transfer has been identified as an important mode of heat transfer during boiling. In this work, we demonstrate that generating additional contact line regions within the base of a nucleating bubble leads to critical heat flux (CHF) enhancement. The creation of a liquid meniscus adjacent to 10–20 μm deep microgrooves in the bubble base area was responsible for the generation of the additional contact line regions. The depth of the microgrooves was determined such that a sufficient reservoir of liquid is present in the meniscus to sustain evaporation in the contact line region throughout the bubble cycle. The effective contact line length at the base of the bubble was seen to be a good indicator of the CHF (wetted area) over the surface. The microgroove geometry played a significant role in influencing the bubble dynamics and bubble departure diameter during boiling. It was seen that the bubbles were able to bridge and grow over the shallow microgrooves of 10–20 μm depth and generate additional contact line regions but were pinned and constrained within the grooves in the case of the microgrooves deeper than 100 μm. For shallow grooves, narrow grooves resulted in smaller bubbles, which in turn reduced the contact line length. The findings of this work could be used to design heat transfer surfaces that significantly enhance the contact line region contribution and CHF by placing shallow enhancement features on the surface of the heater.

Analytical model of the linear inflow to a horizontal well with hydraulic fractures in low-permeability reservoirs

At present, increasing attention has been concentrated on low-permeability deposits whose development is tightly related with technologies of horizontal drilling and hydraulic fracturing of the reservoir. However, the simultaneous presence of a horizontal section of the well and hydraulic fractures in the reservoir impedes the process of flow of reservoir liquids and gases through the porous medium and complicates simulation of such flows. In the present study a new analytical model of the linear inflow to a horizontal well with hydraulic fractures in low-permeability reservoirs is proposed. This is a generalizing model which takes into account both situations when there exists a linear flow in the direction perpendicular to the borehole of a horizontal well in the distant sections of the reservoir and when there is a linear flow in the direction parallel to the borehole of a horizontal well. The use of the model is not restricted by the shape of the flow domain. The new model proposed has a wide application field and does not require complex computations.

Active Cryovolcanism on Europa?

Abstract Evidence for plumes of water on Europa has previously been found using the Hubble Space Telescope using two different observing techniques. Roth et al. found line emission from the dissociation products of water. Sparks et al. found evidence for off-limb continuum absorption as Europa transited Jupiter. Here, we present a new transit observation of Europa that shows a second event at the same location as a previous plume candidate from Sparks et al., raising the possibility of a consistently active source of erupting material on Europa. This conclusion is bolstered by comparison with a nighttime thermal image from the Galileo Photopolarimeter-Radiometer that shows a thermal anomaly at the same location, within the uncertainties. The anomaly has the highest observed brightness temperature on the Europa nightside. If heat flow from a subsurface liquid water reservoir causes the thermal anomaly, its depth is ≈1.8–2 km, under simple modeling assumptions, consistent with scenarios in which a liquid water reservoir has formed within a thick ice shell. Models that favor thin regions within the ice shell that connect directly to the ocean, however, cannot be excluded, nor modifications to surface thermal inertia by subsurface activity. Alternatively, vapor deposition surrounding an active vent could increase the thermal inertia of the surface and cause the thermal anomaly. This candidate plume region may offer a promising location for an initial characterization of Europa’s internal water and ice and for seeking evidence of Europa’s habitability.

Three-Dimensional Bioprinting: Emerging Technology in Cardiovascular Medicine.

With recent advances made in research, we are at a revolutionary and challenging period for 3-dimensional (3D) bioprinting, where a single device (printer) can deposit and layer building blocks of bioink (a composition of cells and structural scaffolds). A key advantage of 3D bioprinting is the ability to produce complex designs from a computer-aided file, making it possible to generate identical copies of patient tissues and organs within 3D space. A wide range of biomaterials are used for 3D printing; similarly, different types of bioprinters have been developed to deposit bioink. Thermal inkjet utilizes a thermal resistor and heat to force down the printing material. Piezoelectric inkjet uses the same approach with a piezoelectric crystal. 3D printers with microextrusion technologies use direct mechanical energy to deposit the printing material. Acoustic picoliters, which are nozzleless bioprinters, use a liquid reservoir that can contain cells as well as a variety of biological materials underneath a series of interdigitized acoustic rings. By adjusting the frequency of acoustic pulse, the size of the droplet can be changed and reduced to sizes that contain single cells with higher cell viabilities. Laser-induced forward transfer also uses a nozzleless approach. Using a series of laser pulses and alternating layers of absorption gelatins, laser-induced forward transfer techniques aim to deliver printing material to a substrate that can result in <95% cell viability. Cardiac valve replacement therapies include the use of mechanical or biological heart valves. …

Solvent fluctuations around solvophobic, solvophilic, and patchy nanostructures and the accompanying solvent mediated interactions.

Using classical density functional theory(DFT), we calculate the density profile ρ(𝐫) and local compressibility χ(𝐫) of a simple liquidsolvent in which a pair of blocks with (microscopic) rectangular cross section are immersed. We consider blocks that are solvophobic, solvophilic and also ones that have both solvophobic and solvophilic patches. Large values of χ(𝐫) correspond to regions in space where the liquid density is fluctuating most strongly. We seek to elucidate how enhanced density fluctuations correlate with the solvent mediated force between the blocks, as the distance between the blocks and the chemical potential of the liquid reservoir vary. For sufficiently solvophobic blocks, at small block separations and small deviations from bulk gas-liquid coexistence, we observe a strongly attractive (near constant) force, stemming from capillary evaporation to form a low density gas-like intrusion between the blocks. The accompanying χ(𝐫) exhibits a structure which reflects the incipient gas-liquid interfaces that develop. We argue that our model system provides a means to understanding the basic physics of solvent mediated interactions between nanostructures, and between objects such as proteins in water that possess hydrophobic and hydrophilic patches.

Thermally anomalous features in the subsurface of Enceladus’s south polar terrain

Saturn’s moon Enceladus is an active world. In 2005, the Cassini spacecraft witnessed for the first time water-rich jets venting from four anomalously warm fractures (called sulci) near its south pole (1,2). Since then, several observations have provided evidence that the source of the material ejected from Enceladus is a large underground ocean, the depth of which is still debated (3,​4,​5,​6). Here, we report on the first and only opportunity that Cassini’s RADAR instrument (7,8) had to observe Enceladus’s south polar terrain closely, targeting an area a few tens of kilometres north of the active sulci. Detailed analysis of the microwave radiometry observations highlights the ongoing activity of the moon. The instrument recorded the microwave thermal emission, revealing a warm subsurface region with prominent thermal anomalies that had not been identified before. These anomalies coincide with large fractures, similar or structurally related to the sulci. The observations imply the presence of a broadly distributed heat production and transport system below the south polar terrain with ‘plate-like’ features and suggest that a liquid reservoir could exist at a depth of only a few kilometres under the ice shell at the south pole. The detection of a possible dormant sulcus further suggests episodic geological activity.

Radon depletion in xenon boil-off gas

An important background in detectors using liquid xenon for rare event searches arises from the decays of radon and its daughters. We report for the first time a reduction of ^{222}Rn in the gas phase above a liquid xenon reservoir. We show a reduction factor of gtrsim 4 for the ^{222}Rn concentration in boil-off xenon gas compared to the radon enriched liquid phase. A semiconductor-based alpha -detector and miniaturized proportional counters are used to detect the radon. As the radon depletion in the boil-off gas is understood as a single-stage distillation process, this result establishes the suitability of cryogenic distillation to separate radon from xenon down to the 10^{-15} mol/mol level.

Corona-induced micro-centrifugal flows for concentration of Neisseria and Salmonella bacteria prior to their quantitation using antibody-functionalized SERS-reporter nanobeads

The use of microcentrifugal flows driven by ionic wind that is generated near a corona needle tip above the level of a small liquid reservoir is a technique to trap suspended bacteria within a few minutes. Gas ions are ejected at the tip of a corona needle to form an ionic wind that can swipe across the liquid/air interface inside a miniaturized reservoir to generate centrifugal vortices. This will drag suspended particles to the center of the reservoir. This article describes a method where antigen-functionalized polystyrene microspheres are first employed to mimic bacteria. The mimetic bacteria were then detected by surface-enhanced Raman scattering (SERS) signal after binding antibody-conjugated nanoaggregate-embedded beads (NAEBs) to antigen-functionalized polystyrene microspheres. The NAEBs were prepared from silica-coated gold nanoparticle aggregates and labeled with Raman reporter molecules. The work demonstrates that the particles can be concentrated at the stagnant point at the bottom of a reservoir containing 60 μL solution only by ionic wind-driven centrifugal flows. SERS signals were acquired to identify the bacteria-mimicking particles. The ionic wind flows were then applied to trap and concentrate Neisseria and Salmonella bacteria bound with antibody-conjugated NAEBs at the level of 106 colony forming units (CFU) per mL (or lower) within 10 min. The NAEBs were preferably labeled with Ethyl violet or fluorescein derivatives. The log-log calibration plot for Neisseria is linear in the 104 to 106 CFU⋅mL−1 concentration range.

A high gas pressure calibration system using a liquid-lubricated pressure balance

Abstract We developed a high gas pressure calibration system that uses a liquid-lubricated (LL) pressure balance as a standard for pressures up to 100 MPa. The LL pressure balance can generate gas or hydraulic pressure by changing the pressure medium. We first evaluate characteristics of the LL piston–cylinder (PC), such as its effective area and fall rate. The effective area of the LL PC is evaluated through comparison with a hydraulic pressure balance. When the LL PC uses a gas, the fall rate is affected by gas dissolution into liquid in the LL PC reservoir. The results of calibrating a pressure gauge under the developed system are consistent with those by an existing hydraulic pressure calibration system.

Experimental and Numerical Studies of CO2 EOR in Unconventional Reservoirs

This article, written by Special Publications Editor Adam Wilson, contains highlights of paper SPE 179634, “Experimental and Numerical Studies of CO2 EOR in Unconventional Liquid Reservoirs With Complex Fracture Networks,” by Jianlei Sun, SPE, Amy Zou, and David Schechter, SPE, Texas A&amp;M University, prepared for the 2016 SPE Improved Oil Recovery Conference, Tulsa, 11–13 April. The paper has not been peer reviewed. This study investigates oil-production mechanisms from the matrix into the fracture by simulating two laboratory experiments as well as several field-scale studies and evaluates the potential of using carbon dioxide (CO2) huff ’n’ puff to enhance oil recovery in unconventional liquid reservoirs (ULRs) with nanodarcy-range matrix permeability and complex natural-fracture networks. This study explores the mechanisms contributing to oil recovery with numerical modeling of experimental work and investigates the effects of various parameters on oil recovery. Introduction CO2 injection has been recognized as one of the more important and successfully applied enhanced-oil-recovery (EOR) processes in the US since the start of the first commercial CO2-injection project in 1972. Statistics show that, out of the 153 active CO2 EOR projects worldwide, 139 of them are in the US. CO2 flooding is the only EOR method in the US that has been consistent and economical since the drop in oil prices in the 1980s. One of the main advantages of CO2 injection is that CO2 can achieve miscibility with the resident hydrocarbon when minimum miscibility pressure (MMP) is attained. Although CO2 flooding has demonstrated the potential of increasing oil production in conventional reservoirs, if this EOR process were to be applied to ULRs, the oil-recovery mechanism could not be considered the same as that during a conventional CO2 flooding because of the differences in reservoir petrophysical properties, fluid-phase behavior, and the fundamental mass-transfer mechanisms. In general, diffusion during gas injection has been recognized as a critical mechanism that affects the oil recovery in fractured reservoirs. If the diffusive flow in the matrix is being neglected during simulation, the calculated result will underestimate productivity. Furthermore, complex fracture geometry has been proposed for hydraulic fracturing because of the intersection between hydraulic fractures and in-situ natural fractures. Numerous simulation and experimental studies have evaluated production performance of complex fracture networks. However, there is no extensive work regarding the potential of CO2 huff ’n’ puff in complex fracture geometries.

SU-8 free-standing microfluidic probes.

We present a process for fabrication of free-standing SU-8 probes, with a dry, mechanical release of the final micro-devices. The process utilizes the thermal release tape, a commonly used cleanroom material, for facile heat-release from the sacrificial layer. For characterization of the SU-8 microfluidic probes, two liquid interfaces were designed: a disposable interface with integrated wells and an interface with external liquid reservoirs. The versatility of the fabrication and the release procedures was illustrated by further developing the process to functionalize the SU-8 probes for impedance sensing, by integrating metal thin-film electrodes. An additional interface scheme which contains electronic components for impedance measurements was developed. We investigated the possibilities of introducing perforations in the SU-8 device by photolithography, for solution sampling predominantly by diffusion. The SU-8 processes described here allow for a convenient batch production of versatile free-standing microfluidic devices with well-defined tip-geometry.